IE URL Lock
While Opera has been my browser of choice since about version version 3, it's handling of certain sites has always been less than stellar - often because of poor (or deliberate) coding on the web site itself. Yahoo webmail is an example of this and Opera's masking feature does not always cut it either.
Over the years, I've messed around with various schemes/free tools to restrict sites that IE can access. However none, including IE's Content Advisor, worked to my satisfaction.
Tonight I came across IE URL Lock on Sourceforge, installed it and within 5 minutes my problems with Yahoo, Gmail and others was over. Well, so it appears anyway. We'll see over the next few days.
Any current users of IE URL Lock, please comment.